Stabilizing means for relay type regulators



Oct. 27, 1942. J, L. KlMB'ALL 2,300,227

STABILIZING MEANS FOR `RELAY TYPE REGULATOS Oct. 27, 1942. J. l.. KIMBALL 2,300,227

STABILIZING MEANS FOR RELAY TYPE REGULATORS Filed Aug. 7, 1941 4 Sheets-Sheet 2 INVENTOR.

Oct. 27, 1942. 1. L KIMBALL 2,300,227

STABILIZING MEANS FOR RELAY TYPE REGULATORS Filed Aug. 7, 1941 4 sheen-sheet 5 IN VENTOR.

www 47M Oct. 27, 1942. J. KlMBALL 2,300,227

STABILIZING MEANS FOR RELAY TYPE REGULATORS Filed Aug. 7, 1941 4 Sheets-Sheet 4 INVENTOR.

the normal governing range.

Patented Oct. 27, 1942 IsrAlLrzrNG. MEANS Foa RELAY TYPE nEGULA'roas James L. Kimball, Danvers, Mass., assignor to Ruggles-Klingemann Mfg. Co., Salem, Mass.

v Appncaunn August 7, 1941,seria1N. 405,801

(ci. 23e- 85) 12 Claims.

This invention relates to regulators of the relay type generally used for the control of dampers, valves or rheostats either from pressure or temperature. Such regulators have a, power motor either hydraulic or electric, a pilot control for controlling a source of power for operating the power motor, either valve or switch, and a device responsive to the condition to be regulated for operating the pilot control to thereby operate the power motor.

Various methods have heretofore been emtion, all of which is objectionable.

My invention, generally stated, has for its object- First, to provide high speed for sudden changes from one load condition, within anormal governing range, to Vanother load conditionoutside the normal governing range; second, to eliminate drift to variations in volume demand and third, to provide an efllcient stabilizing means within Other novel features and combinations tending to increase theI general emciency of the stabilizing means are set forth inl the appended claims.

To accomplish these objects applicant prol vides a governing or stabilized control range of approximately 25% of the total range of the regulators, beyond which the regulator has no damping restraint until stopped by a reversal of the condition under control.

Ordinarily the fluctuations of the volume demand is not so wide as to require more than 25% of the total operating travel of the regulator, but there remains the possibility of a sudden swing from full load to no load and in such a case speed retarding action is objectionable. It is Just as important to guard against the pressure or temperature getting away from the control of the regulator, because of slow response, as it is to guard against over-shooting, because of a lack of damping action. From this it will be seen that applicants regulator should have high speed when speed was required but otherwise to have an effective damping action within the normal governing range. rlhis result has been accomplished by using a step cam having a limited degree of operation, as compared with the total operating range of the regulators, and to provide a slip clutch arrangement for this cam for movements beyond lthe ordinary governing range,V

which permits the cam to be moved into the new regulating position and thereby become effective in any position of the regulator.

The second object of my invention is in the use of what is known as a fluid coupling interconnecting the step-cam with the pilot control. In the fluid coupling method of stabilizing control, whenever equilibrium is attained, the condition under control; as an example, pressure or temperature, will always be the same; that is to say, there will be no drift of a rising and falling scale as in the follow up system of control. The trouble is that, unless the coupling is effective in its operation, equilibrium will never be attained and as a result the regulator will set up a continuous hunting action. Therefore, the third object of my invention is a novel stabilizing arrangement which has been found to be more effective than those heretofore in use. The ordinary fluid coupling comprises a cylinder having a piston therein and involves a stuiling box through which the piston rod extends. The objection to s uch an arrangement is that the friction of the stuillng box impairs the eillciency of the coupling, furthermore, there being no excess fluid within the cylinder, a small amount of leak past the stuiling box allows air to enter the cylinder, which further impairs the eillciency of the coupling.

The novel feature of applicants iluid coupling comprises an oscillating casing with an oscillating plunger therein, each having a common -axis of rotation; with the casing adapted to hold oil in excess of that required for the plunger; the arrangement being such as not to require a stufng box; and in other details, constituting an efflcient connecting link between the operating cam and the pilot control.v

Referring to the drawings,

Fig. 1 shows my invention as applicable to an electric motor operated regulator of the type shown in my Patent No. 1,567,995 of December 29, 1925. I

Fig. 2 shows the elements of the invention as disconnected from the regulator of Fig. l.

Fig. 3 shows my invention as applicable to a hydraulically operated type of regulator of the class shown in my Patent No. 1,597,203 of August 24, 1926.

Fig. 4 shows the arrangement which constitutes my invention as disconnected from the regand spur gear 5. Spur gear 5 is mounted on shaft l the opposite end from that shown extends out on the back side of the gear housing and constitutes the power take-off drive for operating valves, dampers, rheostats or other like devices whose operation'etlects the pressure setting of the regulator, acting through pipe connection 1. The pressure sensitive device 8. which operates reversing switch 9, can be of any suitable construction: a preferred arrangement would be as shown in my Patent No. 1,567,995 of December 29, 1925.

The switch operatinglever II) operates the switch casing II which is of insulating plastic material and supports contact brushes I8, I9 and I9'. A circuit controlling plunger is comprised of part I2 for closing a circuit between I8 and either I9 or I9', and insulating end parts I3 and Il are operated from a cam I5 which is driven from shaft 9 by means of a friction plate I6. The motion imparted by the cam is transmitted through the iiuid coupling II, to govern the pilot switch 9.

This novel arrangement of duid coupling together with the step cam arrangement constitutes appllcants invention, the operation of which is described in detail in connection with Fig. 2.

Referring to Fig. 2, I will now describe the action of the fluid coupling I1. This coupling comprises a casing 2| suspended from shaft 2l which in turn is supported by bracket 2U attached to the gear housing. Mounted on shaft 2l within the casing is arm 26 having a screw stud 24 at its lower end which supports a. ball 25 intended. to transmit angular motion to dash-pot lplung'ers 23 and 23. Shaft 21 is rocked by means oi? bell crank 28 having a roll 29 at the upper end which contacts with cam I5. The arrangement is such that the action of the cam I5 oscillates the plunger 23 and 23 within the end cylinder 22 and 22 the return motion being eected by spring 30. The casing 2I and cylinders and 22 are supplied with light weight transil oil of a sufficient amount to cover the plunger 23 and 23. Casing 2I has an ann 3i which operates contacting plunger I2 by means of connection 32 and 33.

In the operation of this fluid coupling the centering springs 34 and 34' shown in Fig. 1 hold the casing in a centered position and consequently the switch 9 in a neutral position.

Electrical connections indicated by A and B extend to limit switches (not shown) which remain closed until the limit of operation of the regulator has been reached in either of two directions.

On increase in pressure the end of lever IU connected to the control switch cosine `I5 in a clockwise direction.

downward making contact between I9 and I9 which operates motor I in a direction to turn cam I5 counterclockwise as indicated by the arrow. This movement through the action of the plungers 23 and 23' causes the body of the fluid coupling Il to be rocked in a clockwise direction forcing contacting cylinder I2 downward and breaking the circuit. The operation of the controlling apparatus, valve, damper or rheostat, as the case may be, causes the pressure to be reduced and the lever IIl will consequently move upward to its original position at the same time the springs 94 and 34 act to center the fluid coupling into its normal or equilibrium position, as a. result the pressure remains the same as at the beginning of the cycle of operation although the volume flow has been decreased. On a decrease in pressure, as on increase in volume demand, the lever I 0 moves upward moving the switch casing II upward which causes contact to be made between I8 and I9 which operates the motor I in the opposite direction and the cam This operation causes the roll 29 to assume a lower step position which `allows spring 39 to force plungers 29 and 23 to the right thus rocking casing 2i to raise arm 3I and return the switch contacting cylinder I2 toits neutral position. The pressure sensitive device and lever IU have now been returned to their original position through the increase volume flow due to a wider open valve or like device.

The advantage oi the fluid coupling thus described is in the specific arrangement of parts which give it a maximum or effectiveness in maintaining an equilibrium condition of the system for all volume demands.

In cases where time lag between change and correction response is excessive then a heavier oil can be used in the dashpot chamber thus making the coupling more eiiective in avoiding an over-correction due to the transportation lag 0i the system.

I will now explain the operation in which the slip-cam performs an important function. llosuming a sudden demand on the system outside oi the normal load fluctuations or, assuming that the normal demand is close to the maximum. capacity of the control valve or liire device and the volume iiow is suddenly reduced -we then require speed, free from clamping action, :in order that the regulator may .reach e. position corresponding to suoli sudden change in the least possible time. In suol?. a case the cam is moved untill the stud i5 contacts with either one or the opposite end oi slot :it after which the regulator operates without retarding effect into the new load position carrying with it the cam and again establishing stabilized control under the new load condition. There will be some over-travel before a reversal of operation taires place but this will be only what is required to return the control into its stabilized governing zone.

Applicants invention is also applicable to regulators of the hydraulically operated type as shown in Fig. 3, such regulators have a pilot control valve 3l which controls a supply oi fluid under pressure for operating a piston 32 within. a cylinder 39 to control valve or damper as' shown at 49. In principle the stabilizing means is similar to that of the electric motor operated regulator but requires certain changes in construction details to adapt it to regulators of the hydraulic class which will be explained in connection will Fig. 4, reference also being had to Fig. 3.

Diaphragm 4| constitutes a pressure sensitive device adapted to be actuated by the pressure to be regulated. Variation of pressure acting on diaphragm 4| is transmitted by means of pressure cap 42 to lever 43, the total pressure on the diaphragm. being counteracted by spring 44. A iioating arm 4 5 is mounted on lever 43 and serves the purpose of a `ioint control of the pilot valve 31 from the diaphragm and from the step-cam 48. Step-cam 48 is mounted on operating bar 41 which is attached to the piston rod at 48 and operated by piston 38. Step-cam 48 is driven by operating bar 41 by frictional contact therewith in any approved manner. A preferred arrangement is to split the ends and clamp it to this bar by means of threaded screws 68 and 88'. Spring 48 answers the purpose of holding roll 28 in contact with the stepped cam 48. Arm 8| has a link 58 which completes the connection between cam 46 and control valve arm 45. The iluid coupling |1 is rotatively supported from bracket which also acts to guide operating bar 41.

The pilot control valve 31 may be of anysuitable construction, but preferably of the embodiment shown in by Patent No. l.,597,203 already referred to. 'I'he inlet for fluid under pressure is shown at 58 and the exhaust at 51. A port 58 leads to the bottom of the motor piston 38 and a port 59-leads to the top of motor cylinder 39 above the piston. A preferred type of pilot valve has similar mode of operation as a preferred type of pilot switch for electric regulators, namely, that it has a neutral position in which it is not eiective in operating the piston 38 and eiective positions on opposite sides of the neutral position for operating the piston inv either one or the opposite direction.

In the operation of the hydraulic type oi regulator an increase in pressure acting on diaphragm 4| through pipe connection 52 causes right hand end of lever 43 to be raised, thereby actuating pilot valve stem 62 by means of yoke 63 admitting fluid under pressure under piston 38, at the same time opening exhaust port and venting the upper end of the cylinder to atmosphere thus forcing the piston upward to close damper or valve 40. It will be understood that if it were not for the stabilizing means the dampers or valve, as the case might be, would be fully closed, or closed to a point where the pressure acting on diaphragm 4| was reversed which would mean, due to time lag of the system, an over-correction and consequent hunting action.

Applicants stabilizing means acts to check the movement of the piston 38 before reaching a point of over-correction and this is accomplished in the following manner. As operating bar 41 moves upward with the movement of piston 38 it carries with it the step-cam 46 thus forcing arm 28 to the right and dash-pot pistons 23 and 23' to the left, moving casing 2| in the same direction pulling down on arm 50 and adjusting floating lever 45 to return the pilot control valve to its neutral position and checking the operation of the piston 38. This operation means that there will be a reduction oi' pressureacting on diaphragm 4|, as soon as the transportation lag of the system is completed, which normally would cause a reversal `of operation. Simultaneously with the reduction inV pressure centering springs 34 and 34 move the casing 2| in the opposite direction, which raises connecting link 50 and valve stem 6-2 thus compensating for the reduction of pressure on diaphragm 4| and in this way holding the pilot control valve to its neutral or non-etiective position. On a reduction of pressure on diaphrgam 4| the reverse operation takes place and the valve. damper, or like device vis operated step by/ step in either o! two directions .without over-correction or hunting action, within the normal governing range. Now assuming that a sudden change in volume demand took place, which caused the regulator to assume a position outside the normal pressure fluctuating range, then either one or the other end of the cam 48 which is kfrictionally driven from bar 41 will contact with the right hand side of bracket 5|, after whichthe piston 38 can operate at full speed, without any damping action from the fluid coupling, until a reversal in pressure takes place to drive the regulator back into its control zone, after which it `can again operate under stabilized control but under a new volume load condition.

Should the regulator be required for temperature control then all that is necessary is to substitute thermostatic element as shown in Fig.`5 for that of the pressure responsive diaphragm 4| shown in both the electric and hydraulic types of regulators. A thermostatic element consisting of a flexible metal bellows 53, bulb 54, capillary tube 55, containing ether or other volatile liquid suitable for the purpose, although other forms of thermostats may be used without departing from the scope of the invention.

It will be seen by those skilled in the art to Awhich my invention belongs that I have devised novel and useful means for stabilizing regulators of the relay type whereby the speed of the regulator is controlled within the normal operating range to maintain the conditions to be regs.- lated at a uniform value and whereby the regulator has uncontrolled speed outside of the normal operating range.

In accordance with the provisions of the rules of practice of the Patent Office, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent a preferred embodiments thereof: but I desire to have it understood that the apparatus shown is only illustrative and is capable of various modiilcations and that only such limitations shall be imposed as are indicated in the appended claims.

I claim:

1. In a regulator, the combination with a device adapted to control variables of a fluid pressure an element responsive to said variables for operating the pilot control element, a iluid coupling operated from the power motor, in any position thereof co-operating with the responsive device ir. governing the pilot control element, said coupling comprising two cooperating elements with resilient means for centering said coupling at a neutral position and having an effective degree of operation relatively limited as compared to the degree of operation ci! said motor, and a slip clutch interposed between the motor and said coupling.

2. In a regulator, the combination with a device adapted to control variables oi' a pressure system to be regulated, of a motor for operating said device, a pilot control element adapted to control a source of power to operate said motor, a pressure element responsive to a variable of the system for operating the pilot control element, me-

and co-operating with the responsive element for governing the operation of the pilot control element. said means comprising two oscillating elements each being rotatably mounted on a common axis and having resilient means for normally centering said coupling in a position corresponding to the centered position of the pilot control element, and a slip-clutch interposed between the motor and said coupling whereby the motor may be operated to a degree in excess of its normal governing range.

3. In apparatus for the regulation of a condition comprising, in combination, a motor adapted to be actuated by auxiliary power and means operated thereby for controlling the condition of the system. oi a pilot control element adapted to control auxiliary power to actuate said motor, an element responsive to variations in the condition of the system for operating the pilot control element, a multiple step cam operated by said motor,

, eil'ective in any position thereof, and having a governing degree of operation relatively limited as compared with the eilective degree of operation of said motor, means operated by said cam, tvo-operating with said responsive element and said pilot control element, adapted to govern the power motor while operating within the normal uctuating range, and means to permit uncontrolled operation of the power motor outside of said normal nuctuating range, said last means including a slip clutch interposed between the motor and said cam.

4. In a regulator, the combination with a device adapted to control variables in a system to be regulated, of a motor for operating said device, a pilot control element for controlling a source of power to operate said motor, an element responsive to said variables for operating said pilot control element, a step-cam operated by said motor, effective in any position thereof, and movable within the normal fluctuations of said system only, a dash-pot interconnecting said cam with said pilot control element, to thereby adjust said pilot control element to govern the operation of the power motor, while operating within the norn mal fluctuating range, said dash-pot comprising two cooperating elements with resilient means for centering the same at a neutral position, and a slip-clutch interposed between the motor and said cam permitting uncontrolled operation of the power motor outside of said normal fiuctuation range.

5. In a regulator, the combination with a device for controlling variables of a system. to be regulated, of a motor for operating said device, a pilot control element adapted to control a source of auxiliary power to operate said motor, an element resopnsive to variations in the condition of the system for operating the pilot control element, a step-cam operated by said motor, effective in any position thereof, and having governing degree of operation relatively limited as compared with effective degree of operation of said motor, means operated by said cam, co-operating with the responsive element, adapted to govern the pilot control element, said means comprising an oil dash-pot consisting of two reciprocating elements. one of said elements being operated by said cam, and resilient means for normally maintaining said elements in a centered or neutral position and a slip clutch interposed between the motor and said cam.

6. In a regulator, the combination with a device adapted to control variables of a system to be (iii chanical coupling means operatedby the motor' regulated, of a motor for operating said device, a pilot control element adapted to control a source of power to operate said motor, an element responsive to variations in the condition to be regulated for operating the pilot control element, a cam operated by said motor, effective in any position thereof, and having a governing degree of operation relatively limited as compared with the effective degree of operation of said motor, means operated by said cam, co-operating with the responsive element, comprising two oscillating elements each having a common axis, one of said elements includes a dash-pot plunger operated from said cam, the other element comprises the casing for the iirst named element, means connecting the casing with the pilot control, and resilient means for normally maintaining the casing in a centered or neutral position in :relation to the pilot control element and a slip clutch interposed between the motor and said cam.

7. In a regulator having a power motor and a pilot control, a device responsive to the condition to be regulated for operating the pilot control, a fluid actuated coupling operated from the power motor and co-operating with responsive device, for governing the operation of the pilot control, said coupling comprising two oscillating co-operating elements suspended from a stationary support and rotatably mounted on a common axis, one of said elements includes a double ended spool plunger, the other element comprises the casing for the iirst named element, means for operating said plunger from the power motor to thereby actuate the casing, mechanical means operatively connecting the casing with the pilot control and resilient means for normally centering said casing in a position corresponding to the centered position of the pilot control.

8. In a pressure regulator, comprising, in combination, means to control the pressure, a iiuid pressure motor for actuating the pressure com trolling means, a pilot valve having a neutral position and two eiective positions, adapted to control a source of iiuid under pressure, for operating said motor in either one or the opposite din rection, a pressure responsive device for operat-i ing the pilot valve, a fluid coupling operated by the motor and co-operating with the pressure re sponsive device for governing the operation of the pilot valve, said coupling comprising two oscillating co-operating elements rotatably mounted on an axis common to both elements, and having resilient means for normally center ing one of said elements in a neutral position cor responding to the neutral position of said pilot valve, and a slip clutch interposed between the motor and said coupling, whereby the motoi1 may be operated to a degree in excess of the degree of operation of the iluid coupling.

9. l'n a temperature control regulator, com` prising in combination, means to control the ternn perature, a reversible motor for actuating the temperature controlling means, a control element having a'neutral position and two effective posi tions, adapted to control a source of power to operate said motor in either one or the opposite direction, an element responsive to variations in temperature adapted to actuate the control element to either one or the other of its effective positions, mechanical means including a fluid coupling operated by the motor and co-operatim with the temperature responsive element, adapted to govern the operation of the control element, said coupling comprising two oscillating co-oper ating elements rotatably mounted on a common axis and having springs for centering one of said elements in a neutral position corresponding to the neutral position of said control element, and a slip clutch interposed between themotor and said coupling whereby the motor may be operated in excess of the degree of operation of the fluid coupling.

10. In a regulator, the combination with a device adapted to control variables of a'pressure system to be regulated, of a motor for operating said device, a pilot control element having a neutral position and two effective positions adapted to control a source of power to operate said motor in either one or the opposite directions, a pressure responsive element for operating the pilot control element, mechanical means operated by the motor and co-operating withthe pressure responsive device in governing the pilot control element, said means including a cam, a friction clutch, and a fluid coupling, said coupling comprising two cooperating elements and having a resilient means for normally centering one of said elements in a neutral position corresponding to the neutral position of the pilot control, the several elements cooperating to govern to be regulated for operating the pilot control, a fluid actuated coupling operated from the power motor and mechanically co-operating with the responsive device in governing the operation oi the pilot control, said coupling comprising two co-operating elements depending from a stationary support and rotatively mounted on a common axis, means operated by the power motor for operating one of said elements to thereby operate the other element to govern the operation o! the pilot control, and resilient means for normally centering the last named element in relation to a neutralposition of the pilot control.

12. In a regulator having a power motor and a pilot control, a device resopnsive to the condition to be regulated for operating the pilot control, a iiuid coupling interposed between the motor and pilot control, said coupling comprising a casing depending from a stationary support and rotatably mounted thereon, said casing having end caps defining dash pot cylinders for supporting a double ended spool plunger, resilient means for normally centering said casing in an approximately vertical position, means to operate said plunger from said motor to thereby operate said casing to either one or the opposite side of its vertical position, and means operated by the casing co-operating with the responsive element to govern the pilot control.

JAIMES L. MALL. 

